Illustration of the compass surveys: (A) A schematic representation of the compass survey technique. The red dot symbolizes the mooring line, with each circle denoting distance from the mooring in meters, as indicated by the red numerals. The blue line denotes the measuring tape used for the survey. The white area depicts a "dead zone", excluded from the survey due to its relatively small size. Each color-coded concentric belt corresponds to a survey performed by the same diver during different rounds, as indicated by the yellow numerals within the arrows; (B) a pair of divers conducting a survey, counting specimens between their outstretched hands within the one-meter-width belt area.